Galbonolide A (Rustmicin) and Galbonolide B were independently reported in 1985 by Takatoni et al., J. Antibiotics 38, 1807-1809 and Achenbach et al., J. Antibiotics 39, 1760-1764. Galbonolide B was originally isolated as a fungal metabolite from Micromonospora chalcea by Otake and from Streptomyces galbus by Achenbach, independently. The compounds exhibit antifungal activity against a number of fungi including Candida, Fusarium, Rhodotorula and Cryptococcus that are associated with human infections and Botrytis cinerea and Pseudomonas lachrymans that are harmful to agriculture. Galbonolide A and B have been shown to be especially effective against Cryptococcus.
Galbonolide B is claimed in Japanese patent JP 1667737 which issued on May 29, 1992. Galbonolide A is claimed in Japanese patent JP 1667724 which also issued on May 29, 1992. No analogs of Galbonolide A or B have been reported.